1. Field of the Invention
The present invention relates to an exhaust gas cooler for a motor vehicle.
2. Description of the Background Art
Exhaust gas coolers for cooling recirculated exhaust gas are widely used, in particular for the purpose of pollutant reduction. For the most part, exhaust gas coolers are employed in conjunction with diesel engines, but applications for exhaust gas cooling in gasoline engines exist in the meantime, as well.
EP 1 683 956 A1, which corresponds to U.S. Publication No. 20060231243, and which describes a cooler for returned exhaust gas of an internal combustion engine in which a bundle of exchanger tubes is located in a housing through which coolant flows. The coolant enters the housing in the vicinity of an inlet for the exhaust gas and exits the housing in the vicinity of an outlet for an exhaust gas. Located opposite the inlet for the coolant is a small-diameter outlet fitting through which a small partial stream of the coolant exits in order to prevent flow stagnation of the coolant in the inlet region of the exchanger tubes.
These and other prior art exhaust gas coolers are typically incorporated into a secondary flow of a primary cooling circuit of a motor vehicle, or into a branch of a primary cooling circuit that is parallel to an internal combustion engine. In this way, only a small fraction of the total coolant circulation passes through the housings of the prior art exhaust gas coolers.